It's clear that making money online depends on a certain volume of traffic, and there are two ways to get this volume - either set up thousands of pages that each get a tiny amount of traffic, or set up about a hundred pages that each get a large amount of traffic.
At first glance the second strategy looks a lot harder than the first. It's not easy to get a thousand hits a month to each hubpage for instance. I have just one hub that is performing in that league, and hubpages own stats indicate that only 5531 hubs get over 1000 views a month and only 45,515 hubs get over 100 views a month!
Therefore, everyone goes for the content volume method - make thousands of pages, and you get a decent aggregate traffic even if each hub only gets about 50 hits a month.
However, one thing I've learnt is that there is no such thing as truly passive income online. You can't just set up hubs or websites and leave them. You not only have to continue building backlinks to them, I've found that the hubs that do best are the ones that you regularly revise and add information to. You can do this if you are managing a small number of hubs - but when you get to the thousands, it's just impossible to find the time to revise them all regularly as well as build backlinks.
And if you start to get into buying and selling websites, setting up sites with a view to selling them on, you definitely need large traffic in order to realise the best profit - you can't just stick thousands of pages up and leave them, hoping for dribs and drabs of traffic to come to them.
So it looks like the second option - going for a large amount of traffic to each page - though tougher, might be the most profitable in the long run. This means that you have to write long original killer posts, and carefully build backlinks to each and every page. It can't be outsourced and you need to spend a lot of time on research. And there is no instant payoff as with the content volume method. But there should be a payoff down the line when the traffic starts to come in.
I've started to build some standalone sites, with killer posts, and I am working diligently to get each post into the number 1 position in the SERPs for it's phrase. It's a hideous amount of work though, and it looks like I'll be at it for months before I get my traffic volume. I can see why most people abandon this method fairly quickly.